This is a Tall bottle black plate Tung-sol Tube.
This tube was made in the U.S.A. during the 1950's and
has a "U" shaped halo getter.
The TUNG-SOL 6SN7GTB Vacuum Tube is a glass octal type
used as a phase inverter or
resistance-coupled amplifier in radio equipment.
It requires an octal socket and may be mounted in any
position. Each triode unit is independent of the other
except for the common heater.
Electrical Data:
Heater Voltage ................................ 6.3 V
Heater Current ................................ 0.6 A
Maximum Heater-Cathode Voltage Heater Positive with
Respect to Cathode
DC Component ................. 90 V
Heater Negative with Respect to Cathode
DC Component ................. 90 V
Preferred Substitutes ................ 6SN7GTA
Substitutes ...................... 6BL7 6BX7GT